Vacuum extractors for use in childbirth may employ a bell-shaped vacuum cup with a resilient edge adapted to be placed on the scalp of a fetus in the birth canal. A vacuum passage in an elongated hollow stem connects to the interior of the cup through a central hole in the cup and the other end of the stem is connected to a vacuum pump. The vacuum pressure within the cup results in a suction force being applied between the cup and the head which adheres the cup to the fetal scalp. Once the cup is positioned on the head of the fetus, the vacuum extractor can then be used to extract the fetus from the birth canal by manipulating the stem through a handle, or the like.
Devices of this general type are disclosed in U.S. Pat. Nos. 5,019,086, 5,281,229, and 6,361,542. In the United States, vacuum cups typically formed of synthetic plastic and adapted to be disposed after a single use, are generally employed. However, the disposable cups are cost prohibitive in much of the developing world. Sale of disposable cups which are intended for a one-time use, often results in the cup being used multiple times, with issues of sterility, damage to the cup apparatus from multiple use, and tearing of the cup surface which is applied to the fetal scalp.
It would be highly desirable to provide a vacuum cup which is capable of multiple uses, but is designed so as to provide a new, sterile surface for each use. U.S. Pat. No. 5,281,229 discloses an obstetrical vacuum extractor having a liner 30 permanently secured to the interior of the vacuum cup so as to present a soft, flexible surface adapted to contact and line the interior of the vacuum cup. This liner has a central hole 48 which communicates the vacuum provided through the stem to the interior of the cup. The liner is not removable, but is rather welded or otherwise secured to the cup.